[Chemical weed control in the cropping of medicinal plants. Part 1: Valerian (Valeriana officinalis L.) (author's transl)].

More than 40 herbicides have been tested in field trials with valerian over a period of several years. The following herbicidies have proved best suited: chloropham for application in autumn after planting, metobromurone for spraying in the early spring at the commencement of sprouting, nitrofen or a nitrofen-simazine compound preparation for application in May. The utilization of a sequence of herbicides led to a 90% reduction of the weed cover and a 65% reduction of the manual work needed for weed control. The yield and the essential oil and valepotriate contents of valerian were not impaired. The results from residue analyses are presented.